Mask



FIG. 1 is a perspective view of a mask showing my new design;

FIG. 2 is a front view of the mask;

FIG. 3 is a right view of the mask;

FIG. 4 is a left side view of the mask;

FIG. 5 is a top view of the mask;

FIG. 6 is a rear view of the mask; and,

FIG. 7 is a bottom side view of the mask.

The broken lines showing the stitching forms no part of the claimed design. All other broken lines in the drawings depict portions of the mask that form no part of the claimed design. 

CLAIM The ornamental design for a mask, as shown and described. 